Photoelectrolysis of Water under Visible Light with Doped SrTiO3 Electrodes

Various pieces of sintered strontium titanate doped with metal oxides were used as photoanodes in aqueous solutions. Some of them (having Ru, V, Cr, Ce, Co, Rh) caused photocurrents with light in the visible region. The production of oxygen at the semiconductor electrode and hydrogen at the counterelectrode was confirmed. For the electrode doped with , the quantum efficiency of the photocurrents with the visible light (400–500 nm) reached ca. 2% under anodic polarization. Based on these results and the reflection and electroluminescence spectra of the sinter, it is concluded that the photocurrent arises from an electronic transition from a dopant level to the conduction band, the former lying a little above the valence band.